According to the findings from a 2010 study that didn't get any widespread attention, vitamin D is a highly effective way to avoid influenza. In fact, children taking low doses of Vitamin D3 were shown to be 42 percent less likely to come down with the flu.It's Not the Dosage that Matters—It's the Serum LevelSome 40 leading vitamin D experts from around the world currently agree that the most important factor when it comes to vitamin D is your serum level. So you really should be taking whatever dosage required to obtain a therapeutic level of vitamin D in your blood.My doctor recommends40 as a therapeutic level.The Ideal Way to Optimize Your Vitamin D LevelsWhile a lot of the focus on vitamin D ends up being about vitamin D supplementation, the IDEAL way to optimize your vitamin D levels is not by taking a pill, but rather allowing your body to do what it was designed to do—create vitamin D from sun exposure. In a recent interview, Dr. Stephanie Seneff really brought the importance of getting your vitamin D from sun exposure to the fore. While it is consistently recommended getting your vitamin D from regular sun exposure whenever possible, her input explained the wisdom of this natural strategy. She explained that when your skin is exposed to sunshine, it synthesizes not only vitamin D3, but also vitamin D3 sulfate. Your sulfur levels are intricately tied to your cholesterol levels, and plays an important role in the prevention of heart disease. So essentially, getting regular sun exposure has much greater health ramifications than "just" raising your vitamin D levels and preventing infections. Sun exposure also appears to play a role in heart- and cardiovascular health, and much more!Your Flu Might Not Actually be the FluWhen it’s fall or winter and you start to feel feverish with a cough, sore throat, fatigue and body aches, most people automatically think ‘flu.’ If you’ve had the flu vaccine, you may wonder how you still became sick. If you didn’t, you may wish you had. Yet, how many of these illnesses are actually the flu?Most physicians don’t bother to do the laboratory testing required to find out, because the treatment for most flu-like illnesses is the same. Only about 20 percent of all influenza-like illness that occurs every year is actually associated with influenza viruses because many types of respiratory illnesses with flu-like symptoms can be mistaken for influenza. About 80 percent of cases of suspected influenza sent to the CDC for analysis lab test negative for type A or type B influenza.What is also not widely shared is the fact that “most people who get influenza will recover in a few days to less than two weeks” (this is a direct quote from the CDC2).Those who do not are much more likely to be those with compromised immune systems who develop flu-related complications, like pneumonia or bronchitis.A far better approach would be to educate people about the importance of healthy eating, exercise and vitamin D levels – as, unlike the flu vaccine, these natural strategies do help protect against all of the viruses and bacterial infections going around since they work by bolstering your body-wide defense against all disease: your immune system. Vitamin D: Are You Taking Advantage of This Flu-Fighting Nutrient?A universal vaccine being developed by the pharmaceutical company Sanofi is based on the finding that people who have more virus-killing immune cells, known as CD8 T cells, either don’t get sick or experience only mild flu symptoms.3 The idea behind this vaccine is that by stimulating your body to produce more CD8 T cells, it may protect you from getting the flu, or at least from having severe symptoms.They fail to mention that vitamin D is also known to have a direct immune-modulating effect on CD8 T cells. Supplement with the Correct Vitamin D There are two types of vitamin D supplements: vitamin D3 (cholecalciferol), which comes from fish oil, and plant source D2 (ergocalciferol), which is found in fortified foods and some supplements. D2, found in plants and made active by irradiation, is less biologically active.Vitamin D3 is found in eggs, organ meats, animal fat, cod liver oil, and fish. It is equivalent to the vitamin D3 formed on your skin from UV-B. You should stay away from the synthetic D2 as it has been shown to be toxic at the higher dose ranges. You will only want to use vitamin D3 (cholecalciferol).